Improving the surface morphology and crystallite size of isonicotinohydrazide based binuclear Cr(III), Zn(II) and Sn(IV) complexes after irradiation with γ-rays

Abstract

In this work, binuclear Cr(III), Zn(II) and Sn(IV) complexes with: (Z)-N'-(4-methoxybenzylidene)isonicotinohydrazide (L) have been prepared and well assigned and then exposed to gamma ray irradiation with dose up to 100 kGy using Indian 60Co γ-ray cell type GE-4000 A. The structural properties of the synthesized compounds and the structural modifications of the irradiated samples were studied by analytical, magnetic, molar conductance measurements, different spectral (FT-IR, 1H NMR, UV–Vis), powder XRD and thermogravimetry (TG) techniques. The data show that all complexes are dinuclear, Cr(III) complex supposed in distorted teteragonal geometry and Zn(II) complex supposed in distorted square planar geometry have the formula [Cr2L(OH)4]Cl2(1) and [Zn2LCl2(H2O)2]Cl2.3H2O (2), respectively and Sn(IV) has distorted octahedral geometry and the formula is Sn2LCl2(OH)4(H2O)2]Cl2.H2O(3), no geometry change was detected upon irradiation. The XRD of both non-irradiated and irradiated complexes indicate that they are in a nanometer range. A reduction in average crystallite size was observed for irradiated Cr(III) complex. Scanning electron microscopy (SEM) micrographs of [Cr2L(OH)4]Cl2 complex (1) show improving of its crystallinity after γ-irradiation. Further, the solid electrical conductivity of [Zn2LCl2(H2O)2]Cl2.3H2O complex (2) before and after γ-irradiation has been investigated, both samples behaved like insulator. The antimicrobial screening for all metal complexes before and after γ-irradiation was achieved against pathogenic bacteria Staphylococcus aureus as Gram +ve bacteria, Escherichia coli as Gram -ve bacteria and Candida albicans as fungal strain. The results pointed that the metal complexes have moderate antimicrobial activity compared to the standards and in some cases γ-irradiation enhances antimicrobial activity.